N7: Media (Page Info Tab) contents not cached bug?

When using the View|Page Info Menu item I get a nice tabbed window showing information for the page I just loaded. Clicking the Media tab shows what contents the page needed and importantly whether the contents are cached or not. If I load .php pages I am developing off a local server (http://192.168... not accessible from the internet) I see that in the Media tab the "Source" for the gif/jpeg's on my page is listed as "(not cached)" ... but if I look in the cache folder the files are there ... I only see this problem with my local .php pages. I do not have the problem with IE. I do not see this problem if I access .php files on the public Internet. Does N7 have a problem caching files from private (192.168...) networks? Or is N7 really caching the files and there is a problem with the Media (Page Info Tab) in that is incorrectly stating that media has not been cached when it has? Is this a setting in PHP, N7, or Apache I need to change? This is really worrying me so any comments appreciated! Jc